rpi-rgb-led-matrix/lib/framebuffer-internal.h
Henner Zeller 5ce8056334 o Extract framebuffer code to be independent of RGBMatrix.
Preparation to support double buffering.
2014-09-12 20:53:04 -07:00

97 lines
3.5 KiB
C++

// -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
// Copyright (C) 2013 Henner Zeller <h.zeller@acm.org>
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation version 2.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://gnu.org/licenses/gpl-2.0.txt>
#ifndef RPI_RGBMATRIX_FRAMEBUFFER_INTERNAL_H
#define RPI_RGBMATRIX_FRAMEBUFFER_INTERNAL_H
#include "led-matrix.h"
namespace rgb_matrix {
// Internal representation of the frame-buffer that as well can
// write itself to GPIO.
// Our internal memory layout mimicks as much as possible what needs to be
// written out.
class RGBMatrix::Framebuffer {
public:
Framebuffer(int rows, int columns);
~Framebuffer();
// Initialize GPIO bits for output.
static void InitGPIO(GPIO *io);
// Set PWM bits used for output. Default is 11, but if you only deal with
// simple comic-colors, 1 might be sufficient. Lower require less CPU.
// Returns boolean to signify if value was within range.
bool SetPWMBits(uint8_t value);
uint8_t pwmbits() { return pwm_bits_; }
// Map brightness of output linearly to input with CIE1931 profile.
void set_luminance_correct(bool on) { do_luminance_correct_ = on; }
bool luminance_correct() const { return do_luminance_correct_; }
void DumpToMatrix(GPIO *io);
// Canvas-inspired methods, but non-virtual on this level.
inline int width() const { return columns_; }
inline int height() const { return rows_; }
void SetPixel(int x, int y, uint8_t red, uint8_t green, uint8_t blue);
void Clear();
void Fill(uint8_t red, uint8_t green, uint8_t blue);
private:
// Map color
inline uint16_t MapColor(uint8_t c);
const int rows_; // Number of rows. 16 or 32.
const int columns_; // Number of columns. Number of chained boards * 32.
uint8_t pwm_bits_; // PWM bits to display.
bool do_luminance_correct_;
const int double_rows_;
const uint8_t row_mask_;
union IoBits {
struct {
// These reflect the GPIO mapping.
unsigned int unused1 : 2; // 0..1
unsigned int output_enable : 1; // 2
unsigned int clock : 1; // 3
unsigned int strobe : 1; // 4
unsigned int unused2 : 2; // 5..6
unsigned int row : 4; // 7..10
unsigned int unused3 : 6; // 11..16
unsigned int r1 : 1; // 17
unsigned int g1 : 1; // 18
unsigned int unused4 : 3;
unsigned int b1 : 1; // 22
unsigned int r2 : 1; // 23
unsigned int g2 : 1; // 24
unsigned int b2 : 1; // 25
} bits;
uint32_t raw;
IoBits() : raw(0) {}
};
// The frame-buffer is organized in bitplanes.
// Highest level (slowest to cycle through) are double rows.
// For each double-row, we store pwm-bits columns of a bitplane.
// Each bitplane-column is pre-filled IoBits, of which the colors are set.
// Of course, that means that we store unrelated bits in the frame-buffer,
// but it allows easy access in the critical section.
IoBits *bitplane_buffer_;
inline IoBits *ValueAt(int double_row, int column, int bit);
};
} // namespace rgb_matrix
#endif // RPI_RGBMATRIX_FRAMEBUFFER_INTERNAL_H